Losses of a nematic liquid-crystal optical waveguide*

The absorption and scattering losses at 6328 Å in MBBA thin-film waveguides were measured. The absorption loss was studied with a thermal-lens technique and was found to be highly dichroic. Thermal self-focusing was observed for the ordinary ray. The measured scattering losses were between 15 and 40 dB cm−1, depending on the polarization and the liquid-crystal orientation. A modified bulk-scattering loss caused by the thermal fluctuation of the long-range-crystal ordering is calculated and compared with the measurements.